A known calipering device is disclosed in U.S. Pat. No. 4,170,346. In U.S. Pat. No. 4,170,346, the calipering device is in the form of a non-contacting capacitive change measuring device which determines the page count of books as the books move along a bindery assembly line. The calipering device includes a capacitive detector head having a pair of spaced capacitor plates. The pages of each book pass through the space between the plates as the book is conveyed along the bindery assembly line. An oscillator produces a variable frequency of oscillation proportional to the number of pages of the book passing between the plates. The frequency of oscillation is sampled for a predetermined time period. The sampled pulses are counted and compared to a standard within tolerances. The comparison determines whether the page count of the book being measured is acceptable.
A problem associated with some known calipering devices is their relatively poor resolution resulting from the use of some type of magnification arrangement, such as the use of mechanical levers, to magnify a relatively small distance value which is being measured. The magnification arrangement is required to convert the relatively small distance value to a value large enough to be processed by a sensor or a processing unit. The use of such magnification arrangement introduces error into the measured value and thereby limits the resolution of the calipering device.